Need Help, Rough running when cold.

[oldsking]

Okay so I finally took my car out for its first drive and she ran great!! Once it warmd up of course :3d_frown: This was Friday Night.

Basically what happens is when I first start the car up from sitting overnight, it runs very rough, will not hold idle unless I feather the throttle and the vacuum is VERY low. Now once it reaches around 160 F or so, I shut the car off, then restart it and within a few seconds it will idle on its own fine and vacuum is around 10 - 12.

I drove it last night (Saturday) when it was like 48 F and the car wouldnt warm up looks like and it ran like dog shit, lean and popping like crazy.

My set up is as follows which may help for diagnoising

BC 262 cams
Map Ecu with Maf eliminated (File runs good with warm temp looks like)
560 injectors
3" Exhaust and DP
NGK Plugs
180 thermostat (which I think may be the problem?)

Its very annoying as the car will not run with initial start up but after warming up it will and with cold weather around the car not runing right will not help

Need some advice guys! Even Mapecu users can chime in, maybe I need some file tweaking?

 

[Backlash2032]

Do you still have the cold start injector?

 

[oldsking]

I do still have it. Could that be the reason? If it were bad would it make the car lean under cold conditions though? I thought rich

 

[jetjock]

It's a cold start injector, not a cold idle injector...

 

[radiod]

^

Cold start injector is only used for starting. When you said vacuum is between 10 - 12, in what? InHg? psi? I look at 10 - 12 and think...wow...there's a huge vacuum leak there, but I think in InHg.

 

[oldsking]

Yea sorry its psi Haha i think it may be my cams but what is bugging me is that once its warm the car runs pretty decent.

Cold start is out the question then cause it'll fire easily just to stay running is the problem .

---------- Post added at 01:32 PM ---------- Previous post was at 01:30 PM ----------

Yea sorry its psi Haha i think it may be my cams but what is bugging me is that once its warm the car runs pretty decent.

Cold start is out the question then cause it'll fire easily just to stay running is the problem .

 

[radiod]

Well, I can tell you it's not your 180* thermostat, that won't have anything to do with how your engine is running unless your cooling system somehow effects the inside of your combustion chamber, in which case, you have other issues Stock is 190*F if I'm not mistaken.

What is "very low" vacuum on the cold start?

How did you determine that it's running lean? Do you have a wideband and if so, what are the numbers cold vs warm idle?

Have you checked for codes in your ECU?

What type of spark plugs (copper/platinum/iridium?) and what's the gap?

What condition are your plug wires in? Sometimes colder weather can cause cracks in the wires to be more pronounced.

I'm just trying to throw things out there to check so someone will be able to help more, not much info in what's posted in your original post

 

[jetjock]

It's probably that 10-12 psi of vacuum...

 

[oldsking]

I do have a wideband so i know the readings but its hard to get an exact reading usually since its so erratic. Ignition is an is300 conversion which i may be testing to see if thats the pro bled maybe. If its not firing properly it could be a reason i would think? Plugs are ngk coppers gapped at stock specs.

Vacuum readings on cold start up are in the 2-3psi range unless I feather the gas at which point it will raise but the car will not stay idle very well and cut off.

 

[oldsking]

Update, checked ignition it was fine.. I plugged my laptop into my mapecu and found the problem.... somehow with the key open the car was reading nearly 50% throttle opening?!?!? reset that, tried a new map file and it ran much better! Im goin on a ride tonight to test it out so I'll post good news